Browsing by Author "Urry, C. Megan "

Now showing 1 - 20 of 43
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    Accretion history of AGN: Estimating the host galaxy properties in X-ray luminous AGN from z=0-3
    (2022) Coleman, Brandon; Kirkpatrick, Allison; Cooke, Kevin C.; Glikman, Eilat; La Massa, Stephanie; Marchesi, Stefano; Peca, Alessandro; Treister, Ezequiel; Auge, Connor; Urry, C. Megan; Sanders, Dave; Turner, Tracey Jane; Ananna, Tonima Tasnim
    We aim to determine the intrinsic far-Infrared (far-IR) emission of X-ray-luminous quasars over cosmic time. Using a 16 deg(2) region of the Stripe 82 field surveyed by XMM-Newton and Herschel Space Observatory, we identify 2905 X-ray luminous (L-X > 10(42) erg/s) active galactic nuclei (AGN) in the range z approximate to 0-3. The IR is necessary to constrain host galaxy properties such as star formation rate (SFR) and gas mass. However, only 10 per cent of our AGN are detected both in the X-ray and IR. Because 90 per cent of the sample is undetected in the far-IR by Herschel, we explore the mean IR emission of these undetected sources by stacking their Herschel/SPIRE images in bins of X-ray luminosity and redshift. We create stacked spectral energy distributions from the optical to the far-IR, and estimate the median SFR, dust mass, stellar mass, and infrared luminosity using a fitting routine. We find that the stacked sources on average have similar SFR/L-bol ratios as IR detected sources. The majority of our sources fall on or above the main sequence line suggesting that X-ray selection alone does not predict the location of a galaxy on the main sequence. We also find that the gas depletion time scales of our AGN are similar to those of dusty star forming galaxies. This suggests that X-ray selected AGN host high star formation and that there are no signs of declining star formation.
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    Accretion History of AGNs. II. Constraints on AGN Spectral Parameters Using the Cosmic X-Ray Background
    (2020) Ananna, Tonima; Treister, Ezequiel; Urry, C. Megan; Ricci, Claudio; Hickox, R. C.; Padmanabhan, Nikhil; Marchesi, Stefano; Kirkpatrick, Allison
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    BASS XXXIX: Swift-BAT AGN with changing-look optical spectra
    (2023) Temple, Matthew J.; Ricci, Claudio; Koss, Michael J.; Trakhtenbrot, Benny; Bauer, Franz E.; Mushotzky, Richard; Rojas, Alejandra F.; Caglar, Turgay; Harrison, Fiona; Oh, Kyuseok; Gonzalez, Estefania Padilla; Powell, Meredith C.; Ricci, Federica; Riffel, Rogerio; Stern, Daniel; Urry, C. Megan
    Changing-look (CL) AGN are unique probes of accretion onto supermassive black holes (SMBHs), especially when simultaneous observations in complementary wavebands allow investigations into the properties of their accretion flows. We present the results of a search for CL behaviour in 412 Swift-BAT detected AGN with multiple epochs of optical spectroscopy from the BAT AGN Spectroscopic Survey (BASS). 125 of these AGN also have 14-195 keV ultra-hard X-ray light curves from Swift-BAT which are contemporaneous with the epochs of optical spectroscopy. Eight CL events are presented for the first time, where the appearance or disappearance of broad Balmer line emission leads to a change in the observed Seyfert type classification. Combining with known events from the literature, 21 AGN from BASS are now known to display CL behaviour. Nine CL events have 14-195 keV data available, and five of these CL events can be associated with significant changes in their 14-195 keV flux from BAT. The ultra-hard X-ray flux is less affected by obscuration and so these changes in the 14-195 keV band suggest that the majority of our CL events are not due to changes in line-of-sight obscuration. We derive a CL rate of 0.7-6.2 per cent on 10-25 yr time-scales, and show that many transitions happen within at most a few years. Our results motivate further multiwavelength observations with higher cadence to better understand the variability physics of accretion onto SMBHs.
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    BASS. XLV. Quantifying Active Galactic Nuclei Selection Effects in the Chandra COSMOS-legacy Survey with BASS
    (IOP Publishing Ltd, 2025) Tokayer, Yarone M.; Koss, Michael J.; Urry, C. Megan; Natarajan, Priyamvada; Mushotzky, Richard; Balokovic, Mislav; Bauer, Franz Erik; Boorman, Peter; Peca, Alessandro; Ricci, Claudio; Ricci, Federica; Stern, Daniel; Treister, Ezequiel; Trakhtenbrot, Benny
    Deep extragalactic X-ray surveys, such as the Chandra COSMOS-Legacy field (CCLS), are prone to be biased against active galactic nuclei (AGN) with high column densities due to their lower count rates at a given luminosity. To quantify this selection effect, we forward model nearby (z similar to 0.05) AGN from the BAT AGN Spectroscopic Survey (BASS) with well-characterized (greater than or similar to 1000 cts) broadband X-ray spectra (0.5-195 keV) to simulate the CCLS absorption distribution. We utilize the BASS low-redshift analogs with similar luminosities to the CCLS (L-2-10keV(int) similar to 10(42-45) erg s), which are much less affected by obscuration and low-count statistics, as the seed for our simulations and follow the spectral fitting of the CCLS. Our simulations reveal that Chandra would fail to detect the majority (53.3%; 563/1056) of obscured (N-H >= 10(22) cm(-2)) simulated BASS AGN given the observed redshift and luminosity distribution of the CCLS. Even for detected sources with sufficient counts (>= 30) for spectral modeling, the level of obscuration is significantly overestimated. This bias is most extreme for objects whose best fit indicates a high-column density AGN (N-H >= 10(24) cm(-2)), since the majority (66.7%; 18/27) of these are actually unobscured sources (N-H < 10(22) cm(-2)). This implies that previous studies may have significantly overestimated the increase in the obscured fraction with redshift and the fraction of luminous obscured AGN. Our findings highlight the importance of directly considering obscuration biases and forward modeling in X-ray surveys, as well as the need for higher-sensitivity X-ray missions such as the Advanced X-ray Imaging Satellite (AXIS), and the importance of multiwavelength indicators to estimate obscuration in distant supermassive black holes.
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    BASS. XXI. The Data Release 2 Overview
    (2022) Koss, Michael J.; Trakhtenbrot, Benny ; Ricci, Claudio ; Bauer, Franz Erik; Treister, Ezequiel ; Mushotzky, Richard ; Urry, C. Megan ; Ananna, Tonima T. ; Baloković, Mislav ; den Brok, Jakob S. ; Cenko, S. Bradley ; Harrison, Fiona ; Ichikawa, Kohei ; Lamperti, Isabella; Lein, Amy ; Mejía-Restrepo, Julian E. ; Oh, Kyuseok ; Pacucci, Fabio ; Pfeifle, Ryan W. ; Powell, Meredith C. ; Privon, George C. ; Ricci, Federica; Salvato, Mara ; Schawinski, Kevin ; Shimizu, Taro ; Krista L. Smith; Stern, Daniel
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    BASS. XXII. The BASS DR2 AGN Catalog and Data
    (2022) Koss, Michael J. ; Ricci, Claudio ; Trakhtenbrot, Benny ; Oh, Kyuseok ; den Brok, Jakob S. ; Mejía-Restrepo, Julian E. ; Stern, Daniel ; Privon, George C. ; Treister, Ezequiel ; Powell, Meredith C.; Mushotzky, Richard ; Bauer, Franz Erik; Ananna, Tonima T. ; Baloković, Mislav ; Bär, Rudolf ; Becker, George ; Bessiere, Patricia ; Burtscher, Leonard ; Caglar, Turgay ; Congiu, Enrico ; Evans, Phil ; Harrison, Fiona ; Heida, Marianne ; Ichikawa, Kohei ; Kamraj, Nikita; Lamperti, Isabella; Pacucci, Fabio ; Ricci, Federica ; Riffel, Rogério; Rojas, Alejandra F. ; Schawinski, Kevin ; Temple, Matthew J. ; Urry, C. Megan ; Veilleux, Sylvain ; Williams, Jonathan
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    BASS. XXIII. A New Mid-infrared Diagnostic for Absorption in Active Galactic Nuclei
    (2022) Pfeifle, Ryan W.; Ricci, Claudio; Boorman, Peter G.; Stalevski, Marko; Asmus, Daniel; Trakhtenbrot, Benny; Koss, Michael J.; Stern, Daniel; Ricci, Federica; Satyapal, Shobita; Ichikawa, Kohei; Rosario, David J.; Caglar, Turgay; Treister, Ezequiel; Powell, Meredith; Oh, Kyuseok; Urry, C. Megan; Harrison, Fiona
    In this study, we use the Swift/BAT AGN sample, which has received extensive multiwavelength follow-up analysis as a result of the BAT AGN Spectroscopic Survey, to develop a diagnostic for nuclear obscuration by examining the relationship between the line-of-sight column densities (N-H), the 2-10 keV to 12 mu m luminosity ratio, and WISE mid-infrared colors. We demonstrate that heavily obscured AGNs tend to exhibit both preferentially "redder" mid-infrared colors and lower values of L-X,L-Obs./L-12 mu m than less obscured AGNs, and we derive expressions relating N-H to the L-X,L-Obs./L-12 mu m and L-22 mu m/L-4.6 mu m luminosity ratios, as well as develop diagnostic criteria using these ratios. Our diagnostic regions yield samples that are greater than or similar to 80% complete and greater than or similar to 60% pure for AGNs with log(N-H/cm(-2)) >= 24, as well as greater than or similar to 85% pure for AGNs with log(N-H/cm(-2)) greater than or similar to 23.5. We find that these diagnostics cannot be used to differentiate between optically star-forming galaxies and active galaxies. Further, mid-IR contributions from host galaxies that dominate the observed 12 mu m emission can lead to larger apparent X-ray deficits and redder mid-IR colors than the AGNs would intrinsically exhibit, though this effect helps to better separate less and more obscured AGNs. Finally, we test our diagnostics on two catalogs of AGNs and infrared galaxies, including the XMM-Newton XXL-N field, and we identify several known Compton-thick AGNs, as well as a handful of candidate heavily obscured AGNs based upon our proposed obscuration diagnostics.
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    BASS. XXIV. The BASS DR2 Spectroscopic Line Measurements and AGN Demographics
    (2022) Oh, Kyuseok; Koss, Michael J.; Ueda, Yoshihiro; Stern, Daniel; Ricci, Claudio; Trakhtenbrot, Benny; Powell, Meredith C.; den Brok, Jakob S.; Lamperti, Isabella; Mushotzky, Richard; Ricci, Federica; Bar, Rudolf E.; Rojas, Alejandra F.; Ichikawa, Kohei; Riffel, Rogerio; Treister, Ezequiel; Harrison, Fiona; Urry, C. Megan; Bauer, Franz E.; Schawinski, Kevin
    We present the second catalog and data release of optical spectral line measurements and active galactic nucleus (AGN) demographics of the BAT AGN Spectroscopic Survey, which focuses on the Swift-BAT hard X-ray detected AGNs. We use spectra from dedicated campaigns and publicly available archives to investigate spectral properties of most of the AGNs listed in the 70 month Swift-BAT all-sky catalog; specifically, 743 of the 746 unbeamed and unlensed AGNs (99.6%). We find a good correspondence between the optical emission line widths and the hydrogen column density distributions using the X-ray spectra, with a clear dichotomy of AGN types for N (H) = 10(22) cm(-2). Based on optical emission-line diagnostics, we show that 48%-75% of BAT AGNs are classified as Seyfert, depending on the choice of emission lines used in the diagnostics. The fraction of objects with upper limits on line emission varies from 6% to 20%. Roughly 4% of the BAT AGNs have lines too weak to be placed on the most commonly used diagnostic diagram, [O iii]lambda 5007/H beta versus [N ii]lambda 6584/H alpha, despite the high signal-to-noise ratio of their spectra. This value increases to 35% in the [O iii]lambda 5007/[O ii]lambda 3727 diagram, owing to difficulties in line detection. Compared to optically selected narrow-line AGNs in the Sloan Digital Sky Survey, the BAT narrow-line AGNs have a higher rate of reddening/extinction, with H alpha/H beta > 5 (similar to 36%), indicating that hard X-ray selection more effectively detects obscured AGNs from the underlying AGN population. Finally, we present a subpopulation of AGNs that feature complex broad lines (34%, 250/743) or double-peaked narrow emission lines (2%, 17/743).
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    BASS. XXIX. The Near-infrared View of the Broad-line Region (BLR): The Effects of Obscuration in BLR Characterization
    (2022) Ricci, Federica ; Treister, Ezequiel ; Bauer, Franz E.; Mejía-Restrepo, Julian E. ; Koss, Michael J. ; den Brok, Jakob S. ; Baloković, Mislav ; Bär, Rudolf ; Bessiere, Patricia ; Caglar, Turgay ; Harrison, Fiona ; Ichikawa, Kohei ; Kakkad, Darshan; Lamperti, Isabella ; Mushotzky, Richard ; Oh, Kyuseok ; Powell, Meredith C. ; Privon, George C. ; Ricci, Claudio ; Riffel, Rogerio ; Rojas, Alejandra F. ; Sani, Eleonora ; Smith, Krista L. ; Stern, Daniel ; Trakhtenbrot, Benny ; Urry, C. Megan ; Veilleux, Sylvain
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    BASS. XXVI. DR2 Host Galaxy Stellar Velocity Dispersions
    (2022) Koss, Michael J.; Trakhtenbrot, Benny; Ricci, Claudio; Oh, Kyuseok; Bauer, Franz E.; Stern, Daniel; Caglar, Turgay; den Brok, Jakob S.; Mushotzky, Richard; Ricci, Federica; Mejia-Restrepo, Julian E.; Lamperti, Isabella; Treister, Ezequiel; Baer, Rudolf E.; Harrison, Fiona; Powell, Meredith C.; Privon, George C.; Riffel, Rogerio; Rojas, Alejandra F.; Schawinski, Kevin; Urry, C. Megan
    We present new central stellar velocity dispersions for 484 Sy 1.9 and Sy 2 from the second data release of the Swift/BAT AGN Spectroscopic Survey (BASS DR2). This constitutes the largest study of velocity dispersion measurements in X-ray-selected obscured active galactic nuclei (AGN) with 956 independent measurements of the Ca ii H and K lambda 3969, 3934 and Mg I lambda 5175 region (3880-5550 angstrom) and the calcium triplet region (8350-8730 angstrom) from 642 spectra mainly from VLT/X-Shooter or Palomar/DoubleSpec. Our sample spans velocity dispersions of 40-360 km s(1), corresponding to 4-5 orders of magnitude in black hole mass (M (BH) = 10(5.5-9.6) M (circle dot)), bolometric luminosity (L (bol) similar to 10(42-46) erg s(-1)), and Eddington ratio (L/L (Edd) similar to 10(-5) to 2). For 281 AGN, our data and analysis provide the first published central velocity dispersions, including six AGN with low-mass black holes (M (BH) = 10(5.5-6.5) M (circle dot)), discovered thanks to high spectral resolution observations (sigma (inst) similar to 25 km s(-1)). The survey represents a significant advance with a nearly complete census of velocity dispersions of hard X-ray-selected obscured AGN with measurements for 99% of nearby AGN (z < 0.1) outside the Galactic plane ( divide b divide > 10 degrees). The BASS AGN have much higher velocity dispersions than the more numerous optically selected narrow-line AGN (i.e., similar to 150 versus similar to 100 km s(-1)) but are not biased toward the highest velocity dispersions of massive ellipticals (i.e., >250 km s(-1)). Despite sufficient spectral resolution to resolve the velocity dispersions associated with the bulges of small black holes (similar to 10(4-5) M (circle dot)), we do not find a significant population of super-Eddington AGN. Using estimates of the black hole sphere of influence from velocity dispersion, direct stellar and gas black hole mass measurements could be obtained with existing facilities for more than similar to 100 BASS AGN.
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    BASS. XXVIII. Near-infrared Data Release 2: High-ionization and Broad Lines in Active Galactic Nuclei
    (2022) den Brok, Jakob S.; Koss, Michael J.; Trakhtenbrot, Benny; Stern, Daniel; Cantalupo, Sebastiano; Lamperti, Isabella; Ricci, Federica; Ricci, Claudio; Oh, Kyuseok; Bauer, Franz E.; Riffel, Rogerio; Rodriguez-Ardila, Alberto; Baer, Rudolf; Harrison, Fiona; Ichikawa, Kohei; Mejia-Restrepo, Julian E.; Mushotzky, Richard; Powell, Meredith C.; Boissay-Malaquin, Rozenn; Stalevski, Marko; Treister, Ezequiel; Urry, C. Megan; Veilleux, Sylvain
    We present the BAT AGN Spectroscopic Survey (BASS) Near-infrared Data Release 2 (DR2), a study of 168 nearby ((z) over bar = 0.04, z < 0.6) active galactic nuclei (AGN) from the all-sky Swift Burst Array Telescope X-ray survey observed with the Very Large Telescope (VLT)/X-shooter in the near-infrared (NIR; 0.8-2.4 mu m). We find that 49/109 (45%) Seyfert 2 and 35/58 (60%) Seyfert 1 galaxies observed with VLT/X-shooter show at least one NIR high-ionization coronal line (CL; ionization potential chi > 100 eV). Comparing the emission of the [Si VI] lambda 1.9640 CL with the X-ray emission for the DR2 AGN, we find a significantly tighter correlation, with a lower scatter (0.37 dex) than that for the optical [O III] lambda 5007 line (0.71 dex). We do not find any correlation between CL emission and the X-ray photon index Gamma. We find a clear trend of line blueshifts with increasing ionization potential in several CLs, such as [Si VI] lambda 1.9640, [Si X] lambda 1.4300, [S VIII] lambda 0.9915, and [S IX] lambda 1.2520, indicating the radial structure of the CL region. Finally, we find a strong underestimation bias in black hole mass measurements of Sy 1.9 using broad H alpha due to the presence of significant dust obscuration. In contrast, the broad Pa alpha and Pa beta emission lines are in agreement with the M-sigma relation. Based on the combined DR1 and DR2 X-shooter sample, the NIR BASS sample now comprises 266 AGN with rest-frame NIR spectroscopic observations, the largest set assembled to date.
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    BASS. XXXV. The MBH-σ* Relation of 105 Month Swift-BAT Type 1 AGNs
    (IOP Publishing Ltd, 2023) Caglar, Turgay; Koss, Michael J.; Burtscher, Leonard; Trakhtenbrot, Benny; Erdim, M. Kiyami; Mejia-Restrepo, Julian E.; Ricci, Federica; Powell, Meredith C.; Ricci, Claudio; Mushotzky, Richard; Bauer, Franz Erik; Ananna, Tonima T.; Baer, Rudolf E.; Brandl, Bernhard; Brinchmann, Jarle; Harrison, Fiona; Ichikawa, Kohei; Kakkad, Darshan; Oh, Kyuseok; Riffel, Rogerio; Sartori, Lia F.; Smith, Krista L.; Stern, Daniel; Urry, C. Megan
    We present two independent measurements of stellar velocity dispersions (sigma(star)) from the Ca II H+K lambda 3969, 3934 and Mg I b lambda 5183, 5172, 5167 region (3880-5550 angstrom) and the calcium triplet region (8350-8750 angstrom) for 173 hard X-ray-selected Type 1 active galactic nuclei (AGNs; z <= 0.08) from the 105 month Swift-BAT catalog. We construct one of the largest samples of local Type 1 AGNs that have both single-epoch virial black hole mass (M-BH) estimates and sigma(star) measurements obtained from high spectral resolution data, allowing us to test the usage of such methods for supermassive black hole studies. We find that the two independent sigma(star) measurements are highly consistent with each other, with an average offset of only 0.002 +/- 0.001 dex. Comparing M-BH estimates based on broad emission lines and stellar velocity dispersion measurements, we find that the former is systematically lower by approximate to 0.12 dex. Consequently, Eddington ratios estimated through broad-line MBH determinations are similarly biased (but in the opposite way). We argue that the discrepancy is driven by extinction in the broad-line region. We also find an anticorrelation between the offset from the M-BH-sigma(star) relation and the Eddington ratio. Our sample of Type 1 AGNs shows a shallower M-BH-sigma(star) relation (with a power-law exponent of approximate to 3.5) compared with that of inactive galaxies (with a power-law exponent of approximate to 4.5), confirming earlier results obtained from smaller samples.
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    BAT AGN Spectroscopic Survey - XIII. The nature of the most luminous obscured AGN in the low-redshift universe
    (2019) Bar, Rudolf E.; Trakhtenbrot, Benny; Oh, Kyuseok; Koss, Michael J.; Wong, Ivy; Ricci, Claudio; Schawinski, Kevin; Weigel, Anna K.; Sartori, Lia F.; Ichikawa, Kohei; Secrest, Nathan J.; Stern, Daniel; Pacucci, Fabio; Mushotzky, Richard; Powell, Meredith C.; Ricci, Federica; Sani, Eleonora; Smith, Krista L.; Harrison, Fiona A.; Lamperti, Isabella; Urry, C. Megan
    We present a multiwavelength analysis of 28 of the most luminous low-redshift narrow-line, ultra-hard X-ray-selected active galactic nuclei (AGN) drawn from the 70-month Swift/BAT all-sky survey, with bolometric luminosities of log(L-bol/erg s(-1)) greater than or similar to 45.25. The broad goal of our study is to determine whether these objects have any distinctive properties, potentially setting them aside from lower luminosity obscured AGN in the local Universe. Our analysis relies on the first data release of the BAT AGN Spectroscopic Survey (BASS/DR1) and on dedicated observations with the VLT, Palomar, and Keck observatories. We find that the vast majority of our sources agree with commonly used AGN selection criteria which are based on emission line ratios and on mid-infrared colours. Our AGN are pre-dominantly hosted in massive galaxies (9.8 less than or similar to log (M-*/M-circle dot) less than or similar to 11.7); based on visual inspection of archival optical images, they appear to be mostly ellipticals. Otherwise, they do not have distinctive properties. Their radio luminosities, determined from publicly available survey data, show a large spread of almost four orders of magnitude- much broader than what is found for lower X-ray luminosity obscured AGN in BASS. Moreover, our sample shows no preferred combination of black hole masses (M-BH) and/or Eddington ratio (lambda(Edd)), covering 7.5 less than or similar to log (M-BH/M-circle dot) less than or similar to 10.3 and 0.01 less than or similar to lambda(Edd) less than or similar to 1. Based on the distribution of our sources in the lambda(Edd)-N-H plane, we conclude that our sample is consistent with a scenario where the amount of obscuring material along the line of sight is determined by radiation pressure exerted by the AGN on the dusty circumnuclear gas.
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    BAT AGN Spectroscopic Survey. XX. Molecular Gas in Nearby Hard-X-Ray-selected AGN Galaxies
    (2021) Koss, Michael J. ; Strittmatter, Benjamin ; Lamperti, Isabella; Shimizu, Taro ; Trakhtenbrot, Benny ; Saintonge, Amelie ; Treister, Ezequiel ; Cicone, Claudia; Mushotzky, Richard ; Oh, Kyuseok; Ricci, Claudio ; Stern, Daniel ; Tasnim Ananna, Tonima ; Bauer, Franz Erik; Privon, George C. ; Bär, Rudolf ; De Breuck, Carlos; Harrison, Fiona ; Ichikawa, Kohei ; Powell, Meredith C. ; Rosario, David ; Sanders, David B. ; Schawinski, Kevin ; Shao, Li ; Urry, C. Megan ; Veilleux, Sylvain
    We present the host-galaxy molecular gas properties of a sample of 213 nearby (0.01.<.z.<.0.05) hard-X-rayselected active galactic nucleus (AGN) galaxies, drawn from the 70-month catalog of Swift's Burst Alert Telescope (BAT), with 200 new CO(2-1) line measurements obtained with the James Clerk Maxwell Telescope and the Atacama Pathfinder Experiment telescope. We find that AGN in massive galaxies (log(M*/M-circle dot) > 10.5) tend to have more molecular gas and higher gas fractions than inactive galaxies matched in stellar mass. When matched in star formation, we find AGN galaxies show no difference from inactive galaxies, with no evidence that AGN feedback affects the molecular gas. The higher molecular gas content is related to AGN galaxies hosting a population of gas-rich early types with an order of magnitude more molecular gas and a smaller fraction of quenched, passive galaxies (similar to 5% versus 49%) compared to inactive galaxies. The likelihood of a given galaxy hosting an AGN (L-bol > 10(44) erg s(-1)) increases by similar to 10-100 between a molecular gas mass of 10(8.7)M(circle dot) and 10(10.2)M(circle dot). AGN galaxies with a higher Eddington ratio (log(L/L-Edd) > -1.3) tend to have higher molecular gas masses and gas fractions. The log(N-H/cm(-2)) > 23.4) of AGN galaxies with higher column densities are associated with lower depletion timescales and may prefer hosts with more gas centrally concentrated in the bulge that may be more prone to quenching than galaxy-wide molecular gas. The significant average link of host-galaxy molecular gas supply to supermassive black hole (SMBH) growth may naturally lead to the general correlations found between SMBHs and their host galaxies, such as the correlations between SMBH mass and bulge properties, and the redshift evolution of star formation and SMBH growth.
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    Do Moderate-Luminosity Active Galactic Nuclei Suppress Star Formation?
    (2009) Schawinski, Kevin; Treister, Ezequiel; Virani, Shanil; Simmons, Brooke D.; Urry, C. Megan; Kaviraj, Sugata; Kushkuley, Bronika
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    Extended X-ray emission in the IC 2497 - Hanny's Voorwerp system: energy injection in the gas around a fading AGN.
    (2016) Sartori, Lia F.; Schawinski, Kevin; Koss, M.; Treister, Ezequiel; Maksym, W. Peter; Keel, William C.; Urry, C. Megan; Lintott, Chris J.; Wong, O. Ivy
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    GaMPEN: A Machine-learning Framework for Estimating Bayesian Posteriors of Galaxy Morphological Parameters
    (2022) Ghosh, Aritra; Urry, C. Megan; Rau, Amrit; Perreault-Levasseur, Laurence; Cranmer, Miles; Schawinski, Kevin; Stark, Dominic; Tian, Chuan; Ofman, Ryan; Ananna, Tonima Tasnim; Auge, Connor; Cappelluti, Nico; Sanders, David B.; Treister, Ezequiel
    We introduce a novel machine-learning framework for estimating the Bayesian posteriors of morphological parameters for arbitrarily large numbers of galaxies. The Galaxy Morphology Posterior Estimation Network (GaMPEN) estimates values and uncertainties for a galaxy's bulge-to-total-light ratio (L ( B )/L ( T )), effective radius (R ( e )), and flux (F). To estimate posteriors, GaMPEN uses the Monte Carlo Dropout technique and incorporates the full covariance matrix between the output parameters in its loss function. GaMPEN also uses a spatial transformer network (STN) to automatically crop input galaxy frames to an optimal size before determining their morphology. This will allow it to be applied to new data without prior knowledge of galaxy size. Training and testing GaMPEN on galaxies simulated to match z < 0.25 galaxies in Hyper Suprime-Cam Wide g-band images, we demonstrate that GaMPEN achieves typical errors of 0.1 in L ( B )/L ( T ), 0.'' 17 (similar to 7%) in R ( e ), and 6.3 x 10(4) nJy (similar to 1%) in F. GaMPEN's predicted uncertainties are well calibrated and accurate (<5% deviation)-for regions of the parameter space with high residuals, GaMPEN correctly predicts correspondingly large uncertainties. We also demonstrate that we can apply categorical labels (i.e., classifications such as highly bulge dominated) to predictions in regions with high residuals and verify that those labels are greater than or similar to 97% accurate. To the best of our knowledge, GaMPEN is the first machine-learning framework for determining joint posterior distributions of multiple morphological parameters and is also the first application of an STN to optical imaging in astronomy.
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    Lyα emission-line galaxies at z=3.1 in the extended Chandra Deep Field-South
    (2007) Gronwall, Caryl; Ciardullo, Robin; Hickey, Thomas; Gawiser, Eric; Feldmeier, John J.; van Dokkum, Pieter G.; Urry, C. Megan; Herrera, David; Lehmer, Bret D.; Infante, Leopoldo; Orsi, Alvaro; Marchesini, Danilo; Blanc, Guillermo A.; Francke, Harold; Lira, Paulina; Treister, Ezequiel
    We describe the results of an extremely deep, 0.28 deg(2) survey for z = 3.1 Ly alpha emission-line galaxies in the Extended Chandra Deep Field-South. By using a narrowband 5000 angstrom filter and complementary broadband photometry from the MUSYC survey, we identify a statistically complete sample of 162 galaxies with monochromatic fluxes brighter than 1.5 x10(-17) ergs cm(-2) s(-1) and observer's frame equivalent widths greater than 80 angstrom. We show that the equivalent width distribution of these objects follows an exponential with a rest-frame scale length of w(0) = 76(-8)(+11) angstrom In addition, we show that in the emission line, the luminosity function of Ly alpha galaxies has a faint-end power-law slope of -1.49(-0.34)(+0.45) a bright-end cutoff of log L-* = 42.64(-0.15)(,)(+0.26) and a space density above our detection thresholds of (1.46 +/- 0.12); 10(-3) h(70)(3) galaxies Mpc(-3). Finally, by comparing the emission-line and continuum properties of the Ly alpha emitters, we show that the star formation rates derived from Ly alpha are similar to 3 times lower than those inferred from the rest-frame UV continuum. We use this offset to deduce the existence of a small amount of internal extinction within the host galaxies. This extinction, coupled with the lack of extremely high equivalent width emitters, argues that these galaxies are not primordial Population III objects, although they are young and relatively chemically unevolved.
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    Lyα Emission-Line Galaxies at z = 3.1 in the Extended Chandra Deep Field-South.
    (2007) Gronwall, C.; Infante Lira, Leopoldo; Orsi Moyano, Alvaro; Treister, Ezequiel; Ciardullo, Robin; Hickey, Thomas; Gawiser, Eric; Feldmeier, John J.; van Dokkum, Pieter G.; Urry, C. Megan; Herrera, David
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    Lyα-emitting galaxies at z=3.1
    (2007) Gawiser, Eric; Francke, Harold; Lai, Kamson; Schawinski, Kevin; Gronwall, Caryl; Ciardullo, Robin; Quadri, Ryan; Orsi, Alvaro; Barrientos, Felipe; Blanc, Guillermo A.; Fazio, Giovanni; Feldmeier, John J.; Huang, Jia-Sheng; Infante, Leopoldo; Lira, Paulina; Padilla, Nelson; Taylor, Edward N.; Treister, Ezequiel; Urry, C. Megan; Van Dokkum, Pieter G.; Virani, Shanil N.
    We studied the clustering properties and multiwavelength spectral energy distributions of a complete sample of 162 Ly alpha- emitting (LAE) galaxies at z similar or equal to 3: 1 discovered in deep narrowband MUSYC imaging of the Extended Chandra Deep Field-South. LAEs were selected to have observed frame equivalent widths >80 angstrom and emission line fluxes >1.5 x 10(-17) ergs cm(-2) s(-1). Only 1% of our LAE sample appears to host AGNs. The LAEs exhibit a moderate spatial correlation length of r(0) = 3.6(-1.0)(+0.8) Mpc, corresponding to a bias factor b = 1.7(-0.4)(+0.3), which implies median dark matter halo masses of log(10)M(med) = 10.9(-0.9)(+0.5) M-circle dot. Comparing the number density of LAEs, 1.5 +/- 0.3 x 10(-3) Mpc(-3), with the number density of these halos finds a mean halo occupation similar to 1%-10%. The evolution of galaxy bias with redshift implies that most z 3: 1 LAEs evolve into present-day galaxies with L < 2.5L*, whereas other z > 3 galaxy populations typically evolve into more massive galaxies. Halo merger trees show that z 0 descendants occupy halos with a wide range of masses, with a median descendant mass close to that of L*. Only 30% of LAEs have sufficient stellar mass (>similar to 3 x 10(9) M-circle dot) to yield detections in deep Spitzer IRAC imaging. A two-population SED fit to the stacked UBVRIzJK+[3.6, 4.5, 5.6, 8.0] mu m fluxes of the IRAC-undetected objects finds that the typical LAE has low stellar mass (1.0(-0.4)(+0.6) 10(9) M-circle dot), moderate star formation rate (2 +/- 1 M-circle dot yr(-1)), a young component age of 20(-10)(+30) Myr, and little dust (A(V) < 0: 2). The bestfit model has 20% of the mass in the young stellar component, but models without evolved stars are also allowed.